Louisiana, Texas, and Mississippi
I've had experience in Louisiana, Texas, and Mississippi.
(I'm currently in Tx)
Louisiana - has medical, philosophical, and religious exemption. To obtain a philosophical or religious exemption, a parent must write a letter stating that he/she is religiously or philosophically opposed to vaccines. As far as I know, this letter can be turned into schools in place of shot records. No notarizing necessary. I hope that if someone has more or different info on La that she/he will mention it, as my personal experience was 5 years ago.
Texas - has medical, philosophical, and religious exemption. To obtain a philosophical or religious exemption, one must request an exemption from the state (can be done online.) Exemption will arrive in the mail, must be notarized and turned into schools in place of shot records. I just enrolled our girls into two different schools with our exemptions...had no problem whatsoever. Was very easy.
Mississippi - has only medical. Very unfriendly state for non or selective vaccinating families. Unless your child has nearly died from a vaccine (and it's medically documented) don't expect to get an exemption from any doctor (and they require a Mississippi doctor to write the exemption.) If you luck out and get a MS doctor to write the exemption for you, it needs to be approved by the health department. Don't expect it to be approved...it probably won't be. They love to deny waivers. If you are a non or selectively vaccinating family and are planning to live in MS, plan to homeschool.